by Jeff Gluck, USA TODAY Sports

by Jeff Gluck, USA TODAY Sports

MARTINSVILLE, Va. - As if Sunday's race at Martinsville Speedway wasn't already frustrating enough for Jimmie Johnson - he gave up the Sprint Cup Series points lead despite driving at his best track - he had to deal with an angry competitor after the checkered flag.

As Johnson stood on pit road and calmly recounted the events that led to his fifth-place finish, Greg Biffle suddenly came out of nowhere and jerked Johnson's shoulder backward.

"Hey, you (expletive) ripped off my rear bumper, you (expletive)," Biffle said, enraged. "You (expletive) ran into the back of me!"

Johnson protested and said he had position on Biffle, who pointed his finger at the five-time champion and told him to "watch it."

Biffle, who finished ninth, started to walk away as a NASCAR official got between them, but Johnson grabbed his arm. "If you want to talk about it, we can talk about it," he said.

"We just did," Biffle said. "(Expletive), man! I had to go all the way to the back."

Later, Biffle vowed to make sure Johnson wouldn't win a sixth title if he continued to race that way.

"If he's running for the title, he better not tear my rear bumper cover off, because that'll be his last race he finishes," Biffle told reporters.

"The guy tore my rear bumper cover off and I had to pit when we were planning on staying out and I had to go to the tail end of the longest line. That's why I was upset about it."

Johnson acknowledged making contact with Biffle, but replays showed it might have been Dale Earnhardt Jr., not Johnson, who actually tore the bumper off. "We made contact, but I couldn't understand why he was down here pulling on my collar like he just did," Johnson said. "We'll get it sorted out."

Biffle later apologized to Johnson via a tweet: "I Apologize for the way I acted towards @JimmieJohnson after the race,hard racing and I know the bumper had damage already but not dragging"

Johnson, now tied with Matt Kenseth for the Chase lead with three races to go, appeared to be confused, but unfazed by the confrontation with Biffle and a disappointing result.

Johnson, who has won at Martinsville eight times, was expected to expand his points lead over Kenseth, who had never won here nor had many good results. "It's tough, man," Johnson said. "Those (Joe Gibbs Racing) cars are great and he's bonding great with his crew chief. All in all, He's doing what I'd expect."

"I wish he wouldn't have had an awesome day here. I would have loved to have gotten some points on him.

"But when it comes down to the championship at the end of the year, you've got to expect the best out of people and they're certainly doing that right now."

Johnson said he anticipated the final three races - at Texas Motor Speedway, Phoenix International Raceway and Homestead-Miami Speedway - would see the No. 48 team finishing close to Kenseth's No. 20 team each week.

"It'll kind of be a mistake, in my opinion, that will separate things at the end of the year," Johnson said. "We've just got to be clean and not make any mistakes."

Adding to Johnson's frustration level on Sunday was a series of restarts in which he was stuck on the outside of Martinsville's one-groove track. The inside lane had a tremendous advantage, which meant Johnson was shuffled back on several occasions when he restarted in an even-numbered position (the odd numbers get to start on the inside lane).

"That was tough," he said. "Just watching that inside lane march on and just not able to get down and get in a spot. That put us back and it forced our hand to pit a bit early.

"It didn't go our way from a standpoint of lane starts, but that's how it goes."